Apple's co-founder and chairman had struggled with a rare form of pancreatic cancer for a number of years

Steve Jobs, the Apple co-founder who resigned from the company in the mid-1980s and returned a decade later to make Apple one of the most successful technology companies in the world, has died.

Jobs had been struggling with his health for several years. In 2004, he underwent surgery to treat a rare form of pancreatic cancer. He returned to work soon after, but in early 2009 took six months off to treat what he called a "hormone imbalance" that made him appear gaunt and pale. During that leave he underwent a liver transplant. Early this year he took another, indefinite leave of absence to "focus on my health," as he put it, and on Aug. 24 he announced his resignation as CEO, with Chief Operating Officer Tim Cook taking over and Jobs elected board chairman, a position he held until his death.

"We are deeply saddened to announce that Steve Jobs passed away today," Apple's Board of Directors said Wednesday in a statement. "Steve's brilliance, passion and energy were the source of countless innovations that enrich and improve all of our lives. The world is immeasurably better because of Steve."

Jobs will be remembered as a computer visionary but also as a maverick -- a sometimes cantankerous one -- who pursued a doggedly independent path for Apple that could make it frustrating for partners to work with but allowed it to produce unique products. Jobs also ran the hugely successful Pixar Animation Studios for almost 20 years, before selling it to Disney in 2006 for $7.4 billion.

After his return to Apple in 1996, working with the designer Jonathan Ive, Jobs launched a string of products that were admired and emulated for their elegant, sometimes daring design. His brightly colored iMac computers were a sharp break from the two decades of beige PCs that had gone before them. The iPod was a breakthrough in portable music players which, coupled with the iTunes store, changed the music business forever. And the touchscreen iPhone and iPad created whole new categories of products.

Andy Grove, the former chairman and CEO of Intel, has called Jobs the most inspirational leader in Silicon Valley.

Yet by many accounts Jobs was also a difficult man. He was a taskmaster and a control freak whose penchant for secrecy could drive employees and partners to distraction. In 2000, he famously punished graphics vendor ATI for leaking details about future iMacs by pulling its products from some of Apple's computers. His rejection of Flash from the iPhone and seemingly arbitrary policing of the App Store has led to criticism that the company is too closed and insular.

But Jobs had an uncanny knack for reading future trends in computers and consumer electronics, helping Apple to lead the market with must-have products.

He helped ignite the PC revolution with one of the first personal computers, the Apple-1, which he introduced with "the other Steve," Steve Wozniak. Jobs' expertise was in marketing the product while Wozniak focused on technical aspects.

Jobs' entrepreneurial skills became evident at a young age. In 1968, he and a friend created the "blue box," an illegal phone attachment that allowed users to make long distance calls. He also sold and repaired stereos during his high school years.

As a young man he dabbled in counterculture. In 1974, Jobs spent his savings from working at Atari to travel to India, where he sought spiritual enlightenment. He also dated folk music icon Joan Baez in his 20s. He preferred to wear informal attire to work and his favorite musician was Bob Dylan.

Wozniak and Jobs became friends after meeting at Hewlett-Packard in 1971. In 1976, they built the Apple I computer in Wozniak's parents' garage after raising $1,750 -- for which Jobs sold his Volkswagen minibus, and Wozniak his HP scientific calculator.

In 1976, the duo founded Apple Computer Co., named after Jobs had spent a summer working at an Oregon orchard. The company changed its name to Apple Computer Inc. a year later. Apple's second PC, the Apple II, was a success, recording sales of $139 million from 1977-1979.

Steve Jobs, the Apple co-founder who resigned from the company in the mid-1980s and returned a decade later to make Apple one of the most successful technology companies in the world, has died.